Temperature compensated clock frequency monitor

ABSTRACT

A temperature-compensating clock frequency monitor circuit may be provided to detect a clock pulse frequency in an electronic device that may cause erratic or dangerous operation of the device, as a function of an operating temperature of the device. The temperature-compensating clock frequency monitor circuit include a temperature sensor configured to measure a temperature associated with an electronic device, a clock having an operating frequency, and a frequency monitoring system. The frequency monitoring system may be configured to determine the operating frequency of the clock, and based at least on (a) the operating frequency of the clock and (b) the measured temperature associated with the electronic device, generate a corrective action signal to initiate a corrective action associated with the electronic device or a related device. The temperature sensor, clock, and frequency monitoring system may, for example, be provided on a microcontroller.

RELATED PATENT APPLICATION

This application claims priority to commonly owned U.S. ProvisionalPatent Application No. 62/564,828 filed Sep. 28, 2017, the entirecontents of which are hereby incorporated by reference for all purposes.

TECHNICAL FIELD

The present disclosure relates to timing circuits and, moreparticularly, to a temperature-compensated clock frequency monitor.

BACKGROUND

Electronic devices such as microprocessors and microcontrollers (MCUs)include, or have access to, at least one clock running at a knownfrequency to provide a controlled timing for processing instructions,e.g., for executing an application. The operating frequency of suchclocks is often dependent on temperature. For example, RC oscillatortype clocks often have a high temperature coefficient, resulting infrequency variations of up to 50% as a function of temperature, whilecrystal and ceramic resonator-based oscillators typically have a moremoderate temperature coefficient.

These signal frequency variations in processor/MCU clocks may result invarious functional problems, which may be compounded by temperatureeffects on a heat-sensitive device that incorporates the respectiveprocessor or MCU. In some instances, the device operating temperaturehas a strong effect on the maximum operating clock frequency. Forexample, a processor or MCU at a high temperature at high clockfrequency may cause erratic operation, reduced component lifetime, ordevice failure. Thus, for some devices, higher operating temperaturesmay require lower operating frequencies, and similarly, higher operatingfrequencies may require lower temperatures. Furthermore, serialcommunications such as Ethernet, USB, UART, I2C, etc. typically requirecorrect or predictable frequency to avoid communications errors.

Still further, in certain control applications such as power supply andmotor control applications, operating the relevant control loop at anincorrect frequency may causing application or device damage, or dangerto a user. Such electronic devices may include monitors to evaluate theprocessor/MCU clock performance. However, such monitors typically do notcheck for over-frequency operation.

SUMMARY

Embodiments of the present invention provide systems and methods formonitoring the clock signal frequency of a digital clock, e.g., of aprocess or microcontroller as a function of temperature, and taking acorrective action if the monitored clock signal frequency exceeds atemperature-dependent frequency limit. In some embodiments, systems andmethods may include frequency limit logic or circuitry configured toselect, calculate, or otherwise determine a temperature-dependent clockfrequency limit metric, e.g., in the form of a clock pulse limit value(or alternatively, a frequency limit value) based on a sensor detectedtemperature associated with an electronic device. Clock monitoring logicmay implement a clock pulse count window (e.g., using an enable signal,a clear signal, and a reference clock signal), and may count the numberof clock pulses output by the clock being monitored within the definedclock pulse count window. A digital comparator or other logic maycompare the measured clock pulse count with the clock pulse count limitvalue, and based on the output, determine whether to generate aninterrupt signal or other notification for taking a correction action.For example, in some embodiments, an interrupt signal may be generatedif the measured clock pulse count exceeds the clock pulse count limitvalue. An application may process the interrupt signal or initiate otherrelevant corrective measures, e.g., slowing the clock, applying a clockdivider, or activating a cooling mechanism.

One embodiment provides a clock frequency monitor circuit including atemperature sensor configured to measure a temperature associated withan electronic device, a clock having an operating frequency, and afrequency monitoring system. The frequency monitoring system may beconfigured to determine the operating frequency of the clock; determine,based at least on (a) the operating frequency of the clock and (b) themeasured temperature associated with the electronic device, to generatea corrective action signal; and generate the corrective action signal toinitiate a corrective action associated with the electronic device or arelated device.

In some embodiment, the electronic device is a microcontroller or amicroprocessor.

In one embodiment, the temperature sensor, the clock, and the frequencymonitoring system are provided on a microcontroller.

In one embodiment, the frequency monitoring system is configured todetermine a clock frequency limit as a function of the measuredtemperature associated with the electronic device; determine theoperating frequency of the clock; compare the operating frequency of theclock with the clock frequency limit; and generate a corrective actionsignal if the operating frequency of the clock exceeds the clockfrequency limit.

In one embodiment, determining a clock frequency limit based on themeasured temperature associated with the electronic device includesstoring a plurality of clock frequency limit values corresponding with aplurality of different temperatures, and selecting one of the storedclock frequency limit values based on the measured temperatureassociated with the electronic device.

In one embodiment, the frequency monitoring system includes a pluralityof data registers storing a plurality of clock frequency limit valuescorresponding with a plurality of different temperatures, and amultiplexer configured to select a particular clock frequency limitvalue from the plurality of data registers based on the measuredtemperature associated with the electronic device.

In one embodiment, determining the operating frequency of the clockcomprises determining a clock signal count during a defined countwindow.

In one embodiment, generating a corrective action signal comprisesgenerating an interrupt signal for controlling a program application.

In one embodiment, the temperature sensor is configured to measure anambient temperature of an environment of the electronic device.

Another embodiment provides a method for monitoring a clock frequencyincluding measuring using a temperature sensor, a temperature associatedwith an electronic device; measuring an operating frequency of a clock;determining, by frequency monitoring logic, whether to generate acorrective action signal based at least on (a) the measured operatingfrequency of the clock and (b) the measured temperature associated withthe electronic device; and in response to the determination, generatingthe corrective action signal to initiate a corrective action associatedwith the electronic device or a related device.

BRIEF DESCRIPTION OF THE DRAWINGS

Example aspects and embodiments of the present disclosure are describedbelow in conjunction with the following appended drawings:

FIG. 1 illustrates an example temperature-compensated clock frequencymonitor, according to an example embodiment of the present invention;

FIG. 2 illustrates an example temperature-compensated clock frequencymonitor, including clock frequency limit values stored in dataregisters, according to an example embodiment of the present invention;

FIG. 3 illustrates an example method for temperature-compensated clockfrequency monitoring, according to an example embodiment of the presentinvention; and

FIG. 4 illustrates an example electronic device including amicrocontroller having a temperature-compensated clock frequencymonitoring system for identifying and managing temperature-based clockfrequency conditions, according to an example embodiment of the presentinvention.

DETAILED DESCRIPTION

FIG. 1 illustrates an example temperature-compensated clock frequencymonitoring system 100 for monitoring a clock 110, according to anexample embodiment of the present invention. Monitoring system 100 maybe implemented within any suitable electronic device using a clocksignal, such as a microcontroller, processor, or power regulator, forexample. The elements of monitoring system 100 may be implemented byanalog circuitry, digital circuitry, instructions stored in amachine-readable medium for execution by a processor, or any suitablecombination thereof.

System 100 may include at least one temperature-dependent input 102configured to generate or otherwise output temperature-dependent datathat varies as a function of a temperature associated with at least oneelectronic device, e.g., any of the elements of system 100, or a devicein which system 100 is implemented, e.g., as a microcontroller,processor, or power regulator, or any other electronic device. Forexample, temperature-dependent input(s) 102 may include a temperaturesensor configured to detect a temperature of an electronic deviceitself, or an air temperature or ambient temperature proximate theelectronic device. The temperature sensor may generate analog signalsproportional or having another relationship to the measured temperature.System 100 may include an A/D converter 104 to convert analog input data102, e.g., analog temperature sensor signals, to digital data, e.g.,digital temperature value(s). In another embodiment, the temperaturesensor may be a digital sensor configured to output digital temperaturevalues. In some embodiments, e.g., as discussed below with reference toFIG. 2, temperature-dependent input(s) 102 may additionally, oralternatively, include a operational voltage (e.g., A_(dd)) of theelectronic device (e.g., microcontroller, processor, or power regulator,or any other electronic device), which varies as a function of thetemperature of (or associated with) the electronic device.

System 100 may include frequency limit logic or circuitry 106 (e.g.,embodied in hardware and/or software/firmware) configured to calculate,select, or otherwise determine a temperature-dependent clock frequencylimit for clock 110 based on the digital temperature-related datareceived form A/D 104. As discussed below, the value of the frequencylimit may be a quantification or representation of clock frequency thatcan be compared with a measured clock frequency. The frequency limit mayrepresent a minimum or a maximum value for the measured clock frequency,beyond which a warning may be output or an interrupt or other correctiveaction may be taken. For example, the frequency limit may be a maximumallowable clock frequency (or representation thereof) at the temperatureindicated by the temperature-dependent data from input(s) 102 (e.g.,temperature sensor signals). If a measured clock frequency is beyondthis frequency limit, then a warning may be output or an interrupt orother corrective action and notification may be triggered, as discussedbelow.

In the example embodiment shown in FIG. 1 (as well as the embodimentshown in FIG. 2), frequency limit logic or circuitry 106 is configuredto output a frequency limit metric in the form of count limit value,which indicates a maximum or minimum clock pulse count for a specifiedcount window (e.g., based on a reference clock signal). In otherembodiments, frequency limit logic or circuitry 106 may output afrequency limit metric in the form of a frequency value rather than acount limit value. In either case, the frequency limit metric, indicatedas “B,” may be communicated to a digital comparator 108, which mayinclude logic for comparing the frequency limit metric to a measuredclock frequency metric of a clock signal, indicated as “A.” If A isgreater than B, an interrupt may be generated, as discussed below.

The frequency of the clock signal from clock 110 may be measured in anysuitable manner. The manner of measuring or representing the clockfrequency may correspond with the manner of representing the frequencylimit. For example, the clock signal from clock 110 and a referenceclock signal may be input to control logic 112. The control logic 112may generate, in turn, a clock signal to monitor, an enable signal, anda clear signal, and output these signals to a clock pulse counter 114.The output clock signal from clock 110 may be formatted to appropriatelyform pulses that can be counted by the clock pulse counter 114.

Clock pulse counter 114 may use the signals from control logic 112 todefine a count window for measuring the frequency of clock signals fromclock 110. For example, clock pulse counter 114 may begin a runningcount of clock pulses upon receiving an enable signal from control logic112, and end the count upon receiving a clear signal from control logic112. Control logic 112 may control the respective timing of the enableand clear signals based on the reference clock, to thereby provide astandardized/constant count window. Upon reaching the end of the countwindow, the clock pulse counter 114 may output the measured clock pulsecount to the digital comparator 108, which may then comparing thedetermined temperature-dependent frequency limit metric, e.g.,represented by a count limit value, to the measured clock pulse count,as discussed below. (In an alternative embodiment, clock pulse counter114 may calculate a clock frequency value based on the measured clockpulse count, which may be compared to a frequency limit value by digitalcomparator 108).

If digital comparator 108 determines that the measured clock pulse countexceeds the temperature-dependent count limit value (or the measuredclock pulse count is otherwise out-of-bounds), suitable software orother logic instructions 120 may output a warning notification or takeother corrective action. For example, instructions 120 may generate awarning notification that may be output to a user, indicating a high orlow temperature warning. As another example, instructions 120 mayinclude interrupt logic configured to generate an interrupt, alarmsignal, or other relevant notification. Application software may 122handle the interrupt. Other corrective measures, such as slowing theclock 110, applying a clock divider, or activating cooling mechanismsmay be implemented.

In some embodiments, frequency limit logic/circuitry 106, comparator108, and warning/corrective action instructions 120 may provide amulti-level analysis and response based on the magnitude and/or durationof temperature violation. For example, frequency limit logic/circuitry106 may apply multiple different temperature-dependent frequency limitmetrics (e.g. clock pulse count limits) corresponding with multipletemperature thresholds, comparator 108 may compare a measured clockpulse count against multiple temperature-dependent frequency limitmetrics (e.g., multiple clock pulse count limits), andwarning/corrective action instructions 120 may initiate differentresponses based on violations of the different temperature-dependentfrequency limit metrics. For example, warning/corrective actioninstructions 120 may (a) output a warning notification in response to adetermination by comparator 108 that a measured clock pulse countexceeds a first clock pulse count limit value, and (b) initiate acorrective measure (e.g., a software interrupt) in response to adetermination by comparator 108 that the measured clock pulse countexceeds a second clock pulse count limit value, or in response todetermining that the measured clock pulse count exceeds the first clockpulse count limit value for a defined minimum time period.

FIG. 2 illustrates an example temperature-compensated clock frequencymonitoring system 200 for monitoring a clock 210, according to anexample embodiment of the present invention. Monitoring system 200 mayrepresent an embodiment of system 100 shown in FIG. 1, wherein thefrequency limit logic or circuitry 106 for determining atemperature-dependent clock frequency limit includes a plurality ofstored frequency limit values for a plurality of different temperatures,wherein an appropriate one of frequency limit values may be selectedbased on a currently measured temperature, as discussed below in moredetail. Monitoring system 200 may be implemented within any suitableelectronic device using a clock signal, such as a microcontroller,processor, or power regulator, for example. The elements of monitoringsystem 200 may be implemented by analog circuitry, digital circuitry,instructions stored in a machine-readable medium for execution by aprocessor, or any suitable combination thereof.

Like system 100, system 200 may include at least onetemperature-dependent input configured to generate or otherwise outputtemperature-dependent data that varies as a function of a temperatureassociated with at least one electronic device, e.g., any of theelements of system 200, or a device in which system 200 is implemented,e.g., as a microcontroller, processor, or power regulator, or any otherelectronic device. In this example, temperature-dependent input(s) mayinclude a temperature sensor 201 configured to detect a temperatureassociated with an electronic device 202, e.g., a temperature of theelectronic device itself, or an air temperature or ambient temperatureproximate the electronic device. The temperature sensor 201 may generateanalog signals proportional or having another relationship to themeasured temperature. System 202 may also (or alternatively) include, asa temperature-dependent input, a operational voltage (e.g., V_(dd)) ofthe electronic device 202 or another electronic device (e.g.,microcontroller, processor, or power regulator, or any other electronicdevice), which varies as a function of the temperature of (or associatedwith) the relevant electronic device.

An A/D converter 204 may convert analog temperature-dependent inputdata, e.g., analog temperature sensor signals and/or analog V_(dd)signals, to digital data, e.g., digital temperature ortemperature-related value(s).

System 200 may include a plurality of data registers 207 storing aplurality of predefined clock frequency limit values corresponding witha plurality of different predefined threshold temperature metrics, inthis example embodiment three data registers 207A-207C storing threepredefined clock frequency limit metrics, which may for examplecorrespond with three predefined threshold temperatures, e.g., 85° C.,105° C., and 125° C. In one embodiment, the stored clock frequency limitmetrics may decrease as the temperature threshold value increases, asthe maximum allowable clock frequency may decrease as the devicetemperature increases. The predefined clock frequency limit metrics maybe frequency values, pulse count limit values, or any other values thatrepresent a clock frequency limit. In the illustrated example, thepredefined clock frequency limit metrics are pulse count limit valuesthat indicate a maximum or minimum clock pulse count for a specifiedcount window (e.g., based on a reference clock signal).

Further, in some embodiments, one or more predefined clock frequencylimit metrics stored in data registers (e.g., registers 207A-207C) maybe implemented as lower speed limits (or temperature minimumthresholds), such that the system may implements upper speed limits (ormaximum temperature thresholds), lower speed limits (or minimumtemperature thresholds), or any combination thereof.

A multiplexer 206 may be configured to select one of the clock frequencylimit metric (e.g., a clock pulse count limit value) from the dataregisters 207A-207C based on the measured temperature value receivedfrom A/D converter 204. Multiplexer 206 may be configured to treat thethreshold temperature values as upper or lower thresholds with respectto the measured temperature, depending on the particular embodiment. Forexample, where multiplexer 206 treats the threshold temperature valuesas lower thresholds, multiplexer 206 selects the fast speed clockfrequency limit value (from register 207A) for measured temperaturesbelow a first temperature threshold (e.g., 85° C.), selects the mediumspeed clock frequency limit value (from register 207B) for measuredtemperatures above the first temperature threshold but below a secondtemperature threshold (e.g., greater than or equal to 85° C. but below105° C.), and selects the slow speed clock frequency limit value (fromregister 207C) for measured temperatures above the second temperaturethreshold (e.g., 125° C.).

Multiplexer 206 may output the selected frequency limit metric (e.g.,clock pulse count limit value) to digital comparator 208, which mayinclude logic for comparing the frequency limit metric to a measuredclock frequency metric of a clock signal, e.g., as discussed aboveregarding digital comparator 108 of system 100.

The frequency of the clock signal from clock 210 may be measured in anysuitable manner, e.g., in any manner discussed above regarding system100. For example, a clock signal from clock 210 and a reference clocksignal may be input to control logic 212, which may generate and outputa clock signal to monitor, an enable signal, and a clear signal, and toa clock pulse counter 214. Clock pulse counter 214 may use the signalsfrom control logic 212 to define a count window for measuring thefrequency of clock signals from clock 210, e.g., as discussed above.Upon reaching the end of the count window, clock pulse counter 214 mayoutput the measured clock pulse count to the digital comparator 208,which may then comparing the selected temperature-dependent frequencylimit metric, e.g., represented by a count limit value, to the measuredclock pulse count, as discussed below.

If digital comparator 208 determines that the measured clock pulse countexceeds the temperature-dependent count limit value (or the measuredclock pulse count is otherwise out-of-bounds), warning/corrective actionlogic 220 may generate a warning notification, an interrupt, an alarmsignal, or other relevant notification or action. Application softwaremay 222 handle the interrupt. Corrective measures, such as slowing theclock 210, applying a clock divider, or activating cooling mechanismsmay be implemented. As discussed above regarding FIG. 1, in someembodiments, speed limit selection logic 205, comparator 208, andwarning/corrective action logic 220 may provide a multi-level analysisand response based on the magnitude and/or duration of temperatureviolation. For example, comparator 208 may compare the measured clockpulse count from counter 214 against multiple clock pulse count limitvalues stored in registers 207A-207C, and warning/corrective actionlogic 220 may initiate different responses based on violations of thedifferent count limits. For example, warning/corrective action logic 220may (a) output a warning notification in response to a determination bycomparator 208 that a measured clock pulse count exceeds the fast speedcount limit (from register 207C), and (b) initiate a first correctivemeasure (e.g., a software interrupt) in response to a determination bycomparator 208 that the measured clock pulse count exceeds the mediumspeed count limit (from register 207B), and (c) initiate a second, moresevere corrective measure (e.g., shutting down electronic device(s)) inresponse to a determination by comparator 208 that the measured clockpulse count exceeds the slow speed count limit (from register 207A).

FIG. 3 illustrates an example method 300 for temperature-compensatedclock frequency monitoring of a digital clock, e.g., of a processor ormicrocontroller, according to an example embodiment of the presentinvention. Method 300 may incorporate any of the systems, components,and functionality discussed above regarding systems 100 and 200 shown inFIGS. 1 and 2.

At 302, a temperature sensor may generate analog signals proportional toa device temperature, e.g., indicating a temperature of the deviceitself or an environment in which the device is located. In someembodiments, as discussed above, additional temperature-dependent data,e.g., an operating voltage V_(dd) of a relevant electronic device, mayalso be detected or obtained. At 304, an A/D converter may convert theanalog temperature-dependent signals (e.g., sensor signals and/or V_(dd)signals) to digital temperature signals. At 306, frequency limit logicor circuitry may select, calculate, or otherwise determine atemperature-dependent clock frequency limit metric based on thetemperature indicated by the digital temperature signals. The clockfrequency limit metric may be embodied as a clock pulse count limitvalue (for a specified count window), or a frequency value, for example.

At 308, clock monitoring logic (e.g., control logic and pulse countlogic) may implement a clock pulse count window, e.g., using an enablesignal, a clear signal, and a reference clock signal, e.g., as describedabove. At 310, pulse count logic may count the number of clock pulses(from the clock being monitored) within the defined clock pulse countwindow, and output the measured clock pulse count. At 312, a digitalcomparator or other logic may compare the measured clock pulse countdetermined at 310 with the clock pulse count limit value determined at306, and based on the output, generate an interrupt signal or othernotification (e.g., for taking a correction action) at 314. For example,an interrupt signal may be generated if the measured clock pulse countexceeds the clock pulse count limit value (or in another embodiment, ifthe measured clock pulse count is below a clock pulse count minimumlimit value). At 314, a relevant application may process the interruptsignal or initiate other relevant corrective measures, e.g., slowing theclock, applying a clock divider, or activating a cooling mechanism.

FIG. 4 illustrates an example electronic device 400 including aplurality of device components 402 and a microcontroller 404 having atemperature-compensated clock frequency monitoring system foridentifying and managing temperature-based clock frequency conditions,according to an example embodiment of the present invention.Microcontroller 404 may include a clock 410, at least one application412, and a temperature-compensated clock frequency monitoring system414, which may incorporate any of the concepts disclosed above. Forexample, clock frequency monitoring system 414 may be configured todetermine a frequency limit for clock 410 as a function of a devicetemperature measured by at least one temperature sensor 420. The atleast one temperature sensor 420 may be provided in the microcontroller404, or arranged for direct temperature measurement of a particulardevice component 402A, or arranged for measuring an airtemperature/ambient temperature, e.g., within a housing of device 400,or otherwise arranged for measuring a temperature associated withmicrocontroller 404 or electronic device 400. Clock frequency monitoringsystem 414 may be configured to measure a clock pulse frequency of clock410, compare the measured clock pulse frequency to the determinedtemperate-dependent frequency limit, and if the measured clock pulsefrequency exceeds the frequency limit, generate an interrupt forapplication 412 or other signaling for initiating a corrective actionbased on the detected frequency violation.

The invention claimed is:
 1. A clock frequency monitor circuit,comprising: a temperature-related data source configured to providetemperature-related data associated with an electronic device; a clockhaving an operating frequency; a frequency monitoring system configuredto: determine the operating frequency of the clock; determine a clockfrequency limit based at least on (a) the temperature related dataassociated with the electronic device and (b) an operational voltage ofthe electronic device; compare the operating frequency of the clock withthe clock frequency limit; and in response to determining the operatingfrequency of the clock exceeds the clock frequency limit, generate thecorrective action signal to initiate a corrective action associated withthe electronic device or a related device.
 2. The clock frequencymonitor circuit of claim 1, wherein the temperature-related data sourceconfigured to provide temperature-related data associated with anelectronic device comprises a temperature sensor configured to generatesensor signals.
 3. The clock frequency monitor circuit of claim 2wherein the temperature sensor, the clock, and the frequency monitoringsystem are provided on a microcontroller.
 4. The clock frequency monitorcircuit of claim 2, wherein the temperature sensor is configured tomeasure an ambient temperature of an environment of the electronicdevice.
 5. The clock frequency monitor circuit of claim 1, wherein thetemperature-related data associated with the electronic device comprisesa temperature-dependent operational voltage of the electronic device. 6.The clock frequency monitor circuit of claim 1, wherein the electronicdevice comprises a CMOS (complementary metal-oxide-semiconductor)device.
 7. The clock frequency monitor circuit of claim 1, wherein theelectronic device comprises a microcontroller.
 8. The clock frequencymonitor circuit of claim 1, wherein the electronic device comprises amicroprocessor.
 9. The clock frequency monitor circuit of claim 1,wherein determining a clock frequency limit based on the measuredtemperature associated with the electronic device comprises: storing aplurality of clock frequency limit values corresponding with a pluralityof different temperatures; and selecting one of the stored clockfrequency limit values based at least on (a) the measured temperatureassociated with the electronic device and (b) an operational voltage ofthe electronic device.
 10. The clock frequency monitor circuit of claim1, wherein the frequency monitoring system comprises: a plurality ofdata registers storing a plurality of clock frequency limit valuescorresponding with a plurality of different temperatures; and amultiplexer configured to select a particular clock frequency limitvalue from the plurality of data registers based on the measuredtemperature associated with the electronic device.
 11. The clockfrequency monitor circuit of claim 1, wherein determining the operatingfrequency of the clock comprises determining a clock signal count duringa defined count window.
 12. The clock frequency monitor circuit of claim1, wherein generating a corrective action signal comprises generating aninterrupt signal for controlling a program application.
 13. The clockfrequency monitor circuit of claim 1, wherein generating a correctiveaction signal comprises generating a warning notification.
 14. A method,comprising: receiving temperature-related data associated with anelectronic device, the received temperature-related data including atleast a detected temperature-dependent operational voltage of theelectronic device; measuring a temperature-dependent operating frequencyof a first clock of the electronic device using a reference clock signalof a reference clock provided in the electronic device independent ofthe first clock; determining, by frequency monitoring logic, a clockfrequency limit based at least on the detected temperature-dependentoperational voltage of the electronic device; compare the measuredtemperature-dependent operating frequency of the clock with the clockfrequency limit; and determining, by frequency monitoring logic, themeasured temperature-dependent operating frequency of the clock exceedsthe clock frequency limit; and in response to the determination,generating a corrective action signal to initiate a corrective actionassociated with the electronic device or a related device.
 15. Themethod of claim 14, wherein receiving temperature-related dataassociated with an electronic device comprises receiving sensor datafrom a temperature sensor associated with the electronic device.
 16. Themethod of claim 14, wherein the electronic device comprises amicrocontroller.
 17. The method of claim 14, wherein the electronicdevice comprises a microprocessor.
 18. The method of claim 14,comprising: storing a plurality of clock frequency limit valuescorresponding with a plurality of different temperatures; and selectingone of the stored clock frequency limit values based at least on thedetected temperature-dependent operational voltage of the electronicdevice.
 19. The method of claim 14, wherein measuring atemperature-dependent operating frequency of a first clock of theelectronic device using a reference clock signal of a reference clockprovided in the electronic device independent of the first clockcomprises: using the reference clock signal of the reference clock todefine a clock pulse count window; and counting a number of clock pulsesfrom the first clock within the defined clock pulse count window, thecounted number of clock pulses representing the temperature-dependentoperating frequency of the first clock.